First thing I would check is how well the strings are grounded- do you have a wire from the bridge to your grounding point, and if so, is it making good contact with the bridge?

The other thing to check is swap the ground and hot leads on the output jack- when I have problems with noise it's normally because I've reversed the earth.

Had the same on my Squier Telecaster so I dismantled the whole pick up system and shielded it with copper shielding and connected earth wirings between the shielding and all pick ups and bridge etc... Problem solved ?

peterleroux wrote: First thing I would check is how well the strings are grounded- do you have a wire from the bridge to your grounding point, and if so, is it making good contact with the bridge?

+1

I had a funny one on a 70's bass - the pickup had a ground (connected) but everytime I touched the cover I got a hum - sounded like a grounding issue - popped a ground onto the cover and fixed!

Can also use a continuity tester on a multimeter between all the grounding points (bridge to back of pots, jack, etc..) to double check that the ground is getting everywhere it should.

I use copper braid for my grounding. RF travels on the surface, not IN a wire, so the more surface area the better. Cut open old TV antenna cable or whatever to repurpose the old braiding. When shielding cavities I connect them all up with braid too

Checked out the output jack and that is fine. Earth on the bridge seems fine, but I'll probably strip off everything and start afresh. I don't have the patients or electronics skills to do the fault finding necessary! LOL! ?

Not saying that this is your problem, but flourescent lights are a strong source of electrical noise, so avoid playing/testing near to them and don;t share the same electrical circuit as the light, if possible.